1. AVMA Pet Ownership and Demographic Sourcebook. Schaumburg: IL: American Veterinary Medical Associationhttps://ebusiness.avma.org/ProductCatalog/product.aspx?ID=1531
2. Pets by the Numbershttps://www.animalsheltering.org/page/pets-by-the-numbers
3. The Five Freedoms,1992
4. PETS: Ahead of the Curve. Forbeshttps://www.forbes.com/sites/greatspeculations/2018/07/25/pets-ahead-of-the-curve/#25caf8923602